Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:cond-mat/9806315 · Physical Review A

Quantum dynamics of evaporatively cooled Bose-Einstein condensates

P. D. Drummond, Joel Frederick Corney

Published Oct 1, 1999• 100 citations
arXivHTMLPDF

Abstract

We report on dynamical simulations of Bose-Einstein condensation via evaporative cooling in an atomic trap. The results show evidence for spontaneous vortex formation and quantum dynamics in small traps.
DOI
10.1103/physreva.60.r2661

Related papers

Quantum dynamics and coherence properties of evaporatively cooled Bose-Einstein condensates

P. D. Drummond, Joel Frederick Corney

Summary form only given. We report the first successful use of direct quantum dynamical calculations of the cooling and formation of Bose-Einstein condensates of trapped atoms. The calculations utilize phase-space methods that have already proved successful in laser theory. Some of the computational results are very similar to those already observed experimentally. In particular, we find quantum evaporative cooling, followed by a clear transition to a condensate; this is strongly influenced by non-classical features of the quantum dynamics. The calculations indicate additional structure, which we interpret as spontaneous formation of vortices in small condensates. These originate in the residual orbital angular momentum of the trapped atoms, which was neglected in previous studies - and would provide a significant test of the present theory.

Quantum Electronics and Laser Science Conference•Jan 20, 2003•0 citations

Quantum dynamics and coherence properties of evaporatively cooled Bose-Einstein condensates

P. D. Drummond, Joel Frederick Corney

A technique for real-time quantum dynamical simulations of Bose-Einstein condensation (BEC) of large numbers of interacting atoms is demonstrated. Sampling errors and lattice size restrictions mean there are necessary limitations on these first simulations. The results, as well as evidence for highly non-classical behavior in a first principles simulation of BEC formation, indicated the possibility of spontaneous vortex formation in small evaporatively cooled condensates.

•Jan 1, 1999•0 citations

Dynamics of evaporative cooling for Bose-Einstein condensation

Huang Wu, E. Arimondo, Christopher J. Foot

We have simulated the evaporative cooling of a dilute gas of Bose particles including quantum statistics using a Monte Carlo method. This approach can model situations which are far away from quasiequilibrium such as occur during forced evaporative cooling. We have also simulated the dynamical formation of Bose-Einstein condensate for homogeneous and inhomogeneous Bose gases under the random-phase approximation. It was found that the rate of accumulation of Bose particles into low-energy states through collisions is increased by forced evaporation; and a macroscopic population at ground state can be reached at a time scale characterized by classical collision time for an inhomogeneous gas in a harmonic potential. We present the results of simulations for the evaporative cooling and formation of a Bose-Einstein condensate in one-, two-, and three-dimensional position cuts and energy cuts.

Physical Review A•Jul 1, 1997•67 citations

Spontaneous Formation of Quantized Vortices in Bose-Einstein Condensates

Chad N. Weiler

Phase transitions abound in the physical world, from the subatomic length scales of quark condensation to the decoupling forces in the early universe. In the Bose-Einstein condensation phase transition, a gas of trapped bosonic atoms is cooled to a critical temperature. Below this temperature, a macroscopic number of atoms suddenly starts to occupy a single quantum state; these atoms comprise the Bose-Einstein condensate (BEC). The dynamics of the BEC phase transition are the focus of this dissertation and the experiments described here have provided new information on the details of BEC formation. New theoretical developments are proving to be valuable tools for describing BEC phase transition dynamics and interpreting new experimental results. With their amenability to optical manipulation and probing along with the advent of new microscopic theories, BECs provide an important new avenue for gaining insight into the universal dynamics of phase transitions in general.Spontaneous symmetry breaking in the system's order parameter may be one result of cooling through a phase transition. A potential consequence of this is the spontaneous formation of topological defects, which in a BEC appear as vortices. We experimentally observed and characterized the spontaneous formation of vortices during BEC growth. We attribute vortex creation to coherence length limitations during the initial stages of the phase transition. Parallel to these experimental observations, theory collaborators have used the Stochastic Gross-Pitaevski Equation formalism to simulate the growth of a condensate from a thermal cloud. The experimental and theoretical statistical results of the spontaneous formation of vortex cores during the growth of the condensate are in good quantitative agreement with one another, supporting our understanding of the dynamics of the phase transition. We believe that our results are also qualitatively consistent with the Kibble-Zurek mechanism, a universal model for topological defect formation.Ultimately, our understanding of the dynamics of the BEC phase transition may lead to a broader understanding of phase transitions in general, and provide new insight into the development of coherence in numerous systems.

•Jan 1, 2008•1 citation

Magnetic trapping, evaporative cooling, and Bose Einstein Condensation

S. L. Rolston

In these lecture notes I will discuss the techniques of magnetic trapping of neutral atoms and evaporative cooling methods. I will further discuss the observation of Bose Einstein Condensation in weakly interacting gases and summarize some of the experiments that have been performed on the condensates.

AIP conference proceedings•Jan 1, 1999•1 citation

Dynamics of evaporative cooling and growth of a Bose-Einstein condensate

Makoto Yamashita

The dynamics of evaporative cooling of magnetically trapped 87 Rb atoms is studied on the basis of the quantum kinetic theory of a Bose gas. The theoretical optimization of the cooling trajectory clarifies that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against serious three-body recombination loss. The number of condensed atoms is expected to be largely enhanced by the optimization as compared with the typical value produced by the conventional evaporative cooling, where the frequency of the radio-frequency magnetic field is swept exponentially. Next, we precisely examine how the growth of a condensate depends on the experimental parameters of evaporative cooling in this inefficient exponential-sweep cooling. We find that, due to large nonlinear three-body loss, the number of condensed atoms finally becomes insensitive to the initial number of trapped atoms, the initial temperature, and the bias field of a magnetic trap. This result opens up the experimental possibility that the final number of condensed atoms can be well stabilized against the shot-to-shot fluctuations of experimental conditions in evaporative cooling.

Laser Physics•Jan 1, 2004•0 citations
Summary form only given. We report the first successful use of direct quantum dynamical calculations of the cooling and formation of Bose-Einstein condensates of trapped atoms. The calculations utilize phase-space methods that have already proved successful in laser theory. Some of the computational results are very similar to those already observed experimentally. In particular, we find quantum evaporative cooling, followed by a clear transition to a condensate; this is strongly influenced by non-classical features of the quantum dynamics. The calculations indicate additional structure, which we interpret as spontaneous formation of vortices in small condensates. These originate in the residual orbital angular momentum of the trapped atoms, which was neglected in previous studies - and would provide a significant test of the present theory.
We have simulated the evaporative cooling of a dilute gas of Bose particles including quantum statistics using a Monte Carlo method. This approach can model situations which are far away from quasiequilibrium such as occur during forced evaporative cooling. We have also simulated the dynamical formation of Bose-Einstein condensate for homogeneous and inhomogeneous Bose gases under the random-phase approximation. It was found that the rate of accumulation of Bose particles into low-energy states through collisions is increased by forced evaporation; and a macroscopic population at ground state can be reached at a time scale characterized by classical collision time for an inhomogeneous gas in a harmonic potential. We present the results of simulations for the evaporative cooling and formation of a Bose-Einstein condensate in one-, two-, and three-dimensional position cuts and energy cuts.
Phase transitions abound in the physical world, from the subatomic length scales of quark condensation to the decoupling forces in the early universe. In the Bose-Einstein condensation phase transition, a gas of trapped bosonic atoms is cooled to a critical temperature. Below this temperature, a macroscopic number of atoms suddenly starts to occupy a single quantum state; these atoms comprise the Bose-Einstein condensate (BEC). The dynamics of the BEC phase transition are the focus of this dissertation and the experiments described here have provided new information on the details of BEC formation. New theoretical developments are proving to be valuable tools for describing BEC phase transition dynamics and interpreting new experimental results. With their amenability to optical manipulation and probing along with the advent of new microscopic theories, BECs provide an important new avenue for gaining insight into the universal dynamics of phase transitions in general.Spontaneous symmetry breaking in the system's order parameter may be one result of cooling through a phase transition. A potential consequence of this is the spontaneous formation of topological defects, which in a BEC appear as vortices. We experimentally observed and characterized the spontaneous formation of vortices during BEC growth. We attribute vortex creation to coherence length limitations during the initial stages of the phase transition. Parallel to these experimental observations, theory collaborators have used the Stochastic Gross-Pitaevski Equation formalism to simulate the growth of a condensate from a thermal cloud. The experimental and theoretical statistical results of the spontaneous formation of vortex cores during the growth of the condensate are in good quantitative agreement with one another, supporting our understanding of the dynamics of the phase transition. We believe that our results are also qualitatively consistent with the Kibble-Zurek mechanism, a universal model for topological defect formation.Ultimately, our understanding of the dynamics of the BEC phase transition may lead to a broader understanding of phase transitions in general, and provide new insight into the development of coherence in numerous systems.
The dynamics of evaporative cooling of magnetically trapped 87 Rb atoms is studied on the basis of the quantum kinetic theory of a Bose gas. The theoretical optimization of the cooling trajectory clarifies that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against serious three-body recombination loss. The number of condensed atoms is expected to be largely enhanced by the optimization as compared with the typical value produced by the conventional evaporative cooling, where the frequency of the radio-frequency magnetic field is swept exponentially. Next, we precisely examine how the growth of a condensate depends on the experimental parameters of evaporative cooling in this inefficient exponential-sweep cooling. We find that, due to large nonlinear three-body loss, the number of condensed atoms finally becomes insensitive to the initial number of trapped atoms, the initial temperature, and the bias field of a magnetic trap. This result opens up the experimental possibility that the final number of condensed atoms can be well stabilized against the shot-to-shot fluctuations of experimental conditions in evaporative cooling.